Skip to main content
ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Animal Parasitic Diseases Laboratory » Research » Publications at this Location » Publication #352544

Research Project: Detection and Control of Foodborne Parasites for Food Safety

Location: Animal Parasitic Diseases Laboratory

Title: Role of rats (Rattus norvegicus) in the epidemiology of Toxoplasma gondii infection in Grenada, West Indies

item MURATA, FERNANDO - Non ARS Employee
item Kwok, Oliver
item TIWARI, KESHAV - St George'S University
item SU, CHUNLEI - University Of Tennessee
item SHARMA, RAVINDRA - St George'S University
item Dubey, Jitender

Submitted to: Journal of Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/10/2018
Publication Date: 10/25/2018
Citation: Murata, F., Cerqueira-Cezar, C., Kwok, O.C., Tiwari, K., Su, C., Sharma, R., Dubey, J.P. 2018. Role of rats (Rattus norvegicus) in the epidemiology of Toxoplasma gondii infection in Grenada, West Indies. Journal of Parasitology. 104(5):571-573.

Interpretive Summary: Toxoplasma gondii is a single-celled parasite of all warm-blooded hosts worldwide. It causes mental retardation and loss of vision in children, abortion in livestock, and contributes to mortality in wildlife. Cats are the main reservoir of T. gondii because they are the only hosts that can excrete the resistant stage (oocyst) of the parasite in the feces. Epidemiological data indicate that cats become infected with T. gondii by eating tissues if infected animals, most likely rodents and birds. Toxoplasma infection is endemic in humans and livestock in Grenada, West Indies. In the present investigation, the authors assessed the role of infected rats in the epidemiology of toxoplasmosis in Grenada and found very low prevalence (1 of 167 wild caught rats). The results will be useful for parasitologists and biologists.

Technical Abstract: Rodents are known to be reservoir hosts of Toxoplasma gondii infection for other animals, including cats and pigs. From February to July, 2017, 167 rats (Rattus norvegicus) were trapped in Grenada and serum, heart, skeletal muscle and brain were examined for T. gondii infection by serological examination (Modified agglutination test, MAT, 1:25) for T. gondii antibodies and for viable parasites by bioassay in mice. Samples of heart, skeletal muscle and brain of all rats were bioassayed in Swiss Webster (SW) outbred albino mice and interferon gamma gene knockout (KO) mice. Toxoplasma gondii was isolated from heart and brain from 1 rat; this was the only seropositive rat. The T. gondii strain was avirulent for SW mice but killed KO mice. Tissue cysts were detected in the brains of SW mice and tachyzoites were detected in the lungs of KO mice that died of acute toxoplasmosis. The strain was propogated in cell culture and DNA derived from cellcultured tachyzoites was genotyped using the 10 PCR-RFLP (SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1 and Apico). The strain was a clonal Type III (ToxoDB genotype #2) strain. Although the prevalence of T. gondii in humans and animals in Grenada is high, rats seems to have little importance in the transmission of T. gondii in this island.